Fibromyalgia (FM) or FM syndrome is a medical disorder of unknown etiology characterized by chronic widespread joint and muscle pain. Other symptoms include allodynia (a heightened and painful response to pressure), debilitating fatigue, sleep disturbance, and joint stiffness, numbness, tingling and cognitive dysfunction. The etio-pathophysiology of FM is not completely understood, although the syndrome is currently viewed as a malfunctioning of the central nervous system resulting in amplification of widespread pain. In addition, genetic and environmental factors have been suggested to play a role in the etio-pathophysiology of FM.
Although FM is generally regarded as a non-inflammatory and non-autoimmune disease, some patients display autoimmunity features. FM has been found to be common in patients with autoimmune disorders, such as multiple sclerosis, systemic lupus erythematosus (SLE) (Middleton et al. (1994). Arthritis & Rheumatism 37, pp. 1181-1188; Morand, 1994), Sjogren Syndrome (Vitali, 1989; Tishler, 1997) and rheumatoid arthritis (Wolfe, 2004). The widespread pain and inflammation in the musculoskeletal system of FM patients suggest that the immune system may play a role in the etio-pathophysiology of FM. Consequently, studies have been carried out to map the cytokine levels in the serum of FM patients to determine if cytokines play a role in the etio-physiopathology of the disease. (Wallace, D. J., et al., Arthritis and Rheumatism 32:1334-135 (1989); Wallace, D. J., et al., Rheumatology 40:743-749 (2001); Togo, F. et al., Exp. Biol. Med. 234:232-240, (2009); Bazzichi, L. et al., Clin. & Exp. Rheumatol 25:225-230 (2007)). However, the results of these studies have been conflicting (Menzies and Lyon, Biol. Research for Nursing 11:387-394 (2010)) and to date, there is neither a system yet available for evaluating whether an individual with chronic widespread pain has FM or will develop FM, nor a systematic method or criteria for evaluating and diagnosing such individuals. Furthermore, there is no system available that is useful for distinguishing FM from the other autoimmune disorders, which are also characterized by chronic widespread pain.
Accordingly, there is a need for a system useful for diagnosing and evaluating FM to distinguish it from other autoimmune diseases and properly treat the disorder. The present invention addresses this and other needs.